Percussive pneumatic tool



Oct. 30, 1928.

' J. KOHLEN I PERGUSSIVE PNEUMATIC TOOL Filed Jan. 20, 1925 RATE NT OFFICE. j

' JosEr ironnnn, or Hanna, GERMANY.

'rnacossrvn rnnuma'rrc rooL.

npplioation'nled January 20, 1923, Serial No." 613,888, and in Germany June 6,1922.

My present invention relates to percussive pneumatic tools such as rock drills, riveting. hammers, pick-hammers and the like. a The object of my present invention is to obtain a simple and efficient "construction of the operatingmechahisni of tools of the character referred to above, and particularly to en able an ample supply of airvto be governed 'with'the aid of valves of great lightness, and,

therefore, having but-little momentum.

In, the accompanying drawing 'my invention is shown as applied to a pneumatic rock drill, in which drawmg Figure 1 is a longitudinal sectional view of the improved rock, drill; J

Fi are 2 is a cross section taken on the line of Figure 1 Figure 3 is a s milar view taken on the sameline, but with the multivious cock in its shut-oil position;

*Figure 4 is a cross section alsotaken on the line A-C of Figure 1;

Figure 5 is a longitudinal section takenon the line 55 of Figure 2, .Q

Figure '6 is a diagramlllustrating the different positions of the multivious cock, Fig.

7 is a cross section on line 7-*-7 "of Fig. 1" and Fig. 8 is a cross-section on the line A-B of Fig. 1 showing the cock in the position illustrated in Fig. 4.

' The pneumatic rock drill provided with my invention comprises a cylinder 1 wherein a piston 2 is reciprocally operated by the mo tive fluid. To the piston 2 a percussion bar 3 is preferably integrally connected and provided with helical grooves 4 which'merg'e into straight transmitting c lannels 5 a'rranged torun parallel with-the axis of the rock drill. To impart during thee return stroke'of the'piston a partial rotation to the tool, which maybe a tubular drill not shown), in order to enable the-cutting e ges of this drill to chip oflz new particles of stone der 'cover.

during the working stroke of the piston, a chuck 6 is provided, which receives in its squared socket 7 the similarly shaped drillshank, and besides this is provided with tongues 6 adapted to slide but not to rotate in said transmitting channels 5: Above said tool-holder a sleeve 8 is arranged in a housing 9'which guides said percussion bar and simultaneouslg serves as mt'ermediirte cylinton lies 8' in sliding engagement with the wal s of the helical grooves 4, altho ugh withsuflicient play 'to'allow air to pass along the id sleeve is provided with.

bycthe percussion bar and thus brought into a posltion to impart in turn a new partial rotation to the percussion bar during the next return stroke of the piston. The lower part of the sleeve 8 and the tool holder 6 are surrounded by a housing 10 to the lower end of which a drill cage 11 is removably secured.

The motive fluid (generally compressed air) renters the valve chest 12 by Way of a supply channel 13 here s lit 'up into the two branch channels 14 and 5, oi which the former is connected with a valve chamber 16, and the latter with a valve chamber 17. The number ofbranch channels and valve chambers ar-' ranged separately in the valve chest may, of course, be greater than two, if deemed advisable or necessary. In these valve'chambers the ball-valves 18 and'19 are arranged severally and each is adapted toalternately open and close diametrically'opposed,seats formed in thefadjacent ends of inlet channels 20 and 21 respectively (Figure 5). Of these channels the channels 20 communicate with the circular cylinder chamber" 22 and the channels 21 with the annular cylinder chamber 23 to lead the motive fluid alternately to both piston faces, whereas the spent a far higher velocity, said sleeve is rotaterlw motive fluid is carried oil through the exhaust port or ports 24 and 25 respectively.

The ball-valves 18- and 19 work synchronously in parallel and therefore each of them controls but one half of the volume of the motive fluid required for actuatingthe piston.

.Since'the channels 20 and 21 are of a small 7 cross section the ball-valves 18 and 19 can be small, and therefore light, ,and besides this they are only required to execute movements of small amplitude, the wear and tear lot the valves and their seats is reduced to a minimum.

which in operation is lifted off its scat er changes its seats, and does notcmer'ely slide ton face. As the equilibrium of the piston is thus assured the piston is held by friction in thereon. The distinctive feature is that there the position assumed to keep the exhaust port is a plurality of valves instead of the usual single valve. I

The admission and the distribution of the motive fluid is controlled in the rock drill illustrated by a multivious cock, here a threeway cock 26, seated in an enlargement 27 of of ,cylinder and drill, as shown,

the valve chest 12 and adapted to rotate therein on an axis parallel with the common axis The meeting point of the supply channel 13 and of the branch channels 14 and 15 coincides with the l axis of the three-way cock and the arrangedescription of it is deemed superfluous;

ment of these channels is as illustrated in Figures 1-4 inclusive. InFigure 2 the threeway cock is set for the normal working 'operation of the rock drill, designated in Figure 6 as position I. When rotated through an angle of 75 the three-way cock attains the position represented in Figure 3,in which a as position the supply channel 13 is shut-off,

which position is indicated in Figure 6 as position II. An additional rotation of the three-way cock through an angle of 45 will bring it into the position illustrated in F igure 4 and is indicated in Figure 6 as position III. In this last position the branch channels 14 and 15 are closed but the supply channel 13 is brought to register with a semi-circular channel 28 connected with a downwardly directed channel 29 of such length that when brought in the position illustrated in Figure 4it freely communicates with alport 30 which leads to the annular cylinder-chamber 23. In

this position of the threeway cook 26 the exhaust port 25 is closed (Figure 4). On the;

introduction of motive fluid into the annular cylinder-cha'mber23 through the ehannels 13, 28, 29 and the port 30, the piston 2 will be retracted until the helical grooves 4 arebrought into communication with the cylinder-chamber 23; During this retraction ofthe piston a'compr'ession. of the gaseous contents of the circular cylinder-chamber 22 t akes place. and prevents the piston 2 from uncovering the ex"- haust port 24. Since the cross-sectional area of the grooves 4 is not completely closed by the tongues 8, nor that of the transmitting channels 5 by the tongues 6, the live motive fluid admitted to the annularjcylinder cham ber 23 can pass freely through these channels, advance through the tubular drill to the bot.- tom of the bore-hole, and-completely remo e the stone-dust from the latter by blowing'it upward and out of the mouth of the bore-hole.

'When the live motive fluid on its downward,- way reaches the recess 31 of the tubular tool holder a part of it flows through a central lonq gitudinal bore 32, common to percussion .bar I and piston, into the circular cylinder-chamber closed. When shallow bore-holes are driven into dry rock the small jet of motive fluid which passes at each working stroke of the piston through the longitudinal bore 32 to the bottom of the bore-hole suflicesto blow out the stone-dust but in all other cases it is preferably blown out as indicated above.

Since the general operation of the rock drill is well known in all its phases," and besides this may be readily understood with the aid of theaccompanying drawing, a detailed The severalparts of the drill are kept'in alignment and resilient contact one with an-v other by bolts 33 which pass through the external cylinder cover 34 provided with a han-'. dle 35 andthrough lateral lugs 36 of the housing 10 between which lugs and the nuts 37 of the bolts helical springs 38 are arranged, as

indicated by dotted lines inFigure 1.

cate therein, said cylinder having two exhaust ports arranged to be uncovered by the piston alternately but solocated that in cer-.: tain. positions of the piston both exhaust ports will be covered thereby, a cock which controls the one, exhaust port of the cylinder,

and channels, likewise controlled bysaid cock, for. leading the medium under, pressure alternately to opposite ends of -said cylinder, said cock being arranged to conduct the medium under pressure to one end of the cylinder at the sametime that said cock closes the exhaust port leading from that cylinder end.

2. A (percussive pneumatic tool comprising a cylin er anda piston arranged to reciprocate therein, and provided with a percussion bar held to reciprocate with said piston and provided with grooves arranged to communicate at times with one end of said cylinder to allow the motive medium under pressureto blow out at the surface worked by the tool, said cylinder having two exhaust ports arranged to be covered by said piston alters nately, and a cock for admitting motive fluid under pressure or shutting oflz such fluid, to

or from channels leading to opposite ends of the cyllnder, said cock also having a position 3. A percussive pneumatic-to", comprising a cylinder, a piston arranged to reciprocate therein, and a percussion bar held to re tive fluid to said cylinder channels alternately, while in another position said cock'shuts 0E ciprocate with said piston and provided with channels arranged to. communicate at times with one end of the cylinder to allow the motive fluid under pressure to blow out at the surface worked by the tool, said cylinder being provided with channels to admit such fluid under pressure alternately to opposite ends of the cylinder, and also having exhaust ports arranged to be uncovered by said piston alternately, and a cock which in one position opens the exhaust port for that end of the cylinder through which the percussion bar extends, and at the same time admits the mothe admission of motive fluid entirely while still leaving the exhaust port open, and in a third position said cock closes said exhaust port, but admits motive fluid to the cylinder end adjacent to said exhaust port.

4. A percussive pneumatic tool comprising a cylinder having inlet ports at opposite ends and exhaust ports at ditferent distances from its ends, a piston arranged to reciprocate in said cylinder and controlling the exhaust ports thereof, a percussion bar held to reciprocate with said piston and provided with grooves arranged to communicate at times with one end of said cylinder to allow the motive medium under pressure to blow out at the surface worked by the tool, the said piston and percussion bar being provided with a longitudinal channel communicating with the other end of the cylinder, and a cock controlling the outlet of the exhaust port which is connected with the cylinder end containing the percussion bar, said cock also operating to establish or shut off the supply of motive, fluid to the ends of the cylinder.

5. A percussive pneumatic tool comprising a cylinder provided with a plurality of valve chambers. means for admitting like amounts of a pressure medium to each of said valve chambers, a piston arranged to reciprocate in said cylinder, channels for conducting said medium under pressure from each of said valve chambers to opposite ends of said cylinder; and floating valves of like weight, constructions and stroke solely operated by said pressure medium. and arranged to move coincidentally and in parallel in the respective valve chambers and operating to connect these chambers with opposite ends of the cylinder alternately.

6. A percussive pneumatic tool comprising a cylinder provided with a pair of valve chambers arranged side by side, branch channels connecting said valve chambers independently of each other with the inlet of a pressure medium and adapted to admit like amounts of such pressure medium to each of said valve chambers, a iston arranged to reciprocate in said cylin er, channels for conducting said medium under pressure from each of said valve chambers to op osite ends of said cylinder, and two floating all valves of like weight and stroke solely operated by said pressure medium and arranged to move coincidentally and in parallel in the'respective valve chambers and operating to connect these chambers with opposite ends of the cylinder alternately.

7. A percussive pneumatic tool comprising a'c linder provided with a plurality of valve 0 ambers, a piston arranged to recip rocate in said cylinder, channels for conductinga medium under pressure from each of said chambers to opposite ends of said cylinder; and a single distributin cock adjustable to one position for admitting like amounts of such pressure medium simultaneousl to each of said valve chambers, and to anot er posi-, tion for shutting off the suppl of such medium from said chambers an to lead said medium through the front end of the c linder to the bore hole of the tool when sai piston on its return stroke reaches a certain position in the cylinder.

Signed by me at Cologne, Germany, this 28th day of December, 1922.

' JQSEF. KOHLEN. 

